Combustor heat shields provide protection to the dome portion of the combustor shell. The heat shields may be provided with radially inner and radially outer lips. These lips are exposed to high gas temperature relative to the remainder of an otherwise well-cooled heat shield, resulting in high thermal gradients. The thermal gradient inevitably results in cracks due to thermal mechanical fatigue. Cracking in the lips further deteriorates cooling effectiveness and results in additional damage due to high temperature oxidation.
Accordingly, there is a need for an improved cooling scheme while avoiding any detrimental effect on the rest of the heat shield surface cooling.